The space rock at the time of the dinosaurs, wasn't just to kill off the dinosaurs, but also to increase earth's necessary elements for new life. Us. In a time before telescopes, in a time when radar was un-known, they came.
They exist with us and have yet to disclose via any transmission so far, and thus none have been recorded. So far. Perhaps the informational data levels do not as yet warrant transmitting, from their interstellar minds point of view. With integration so finely tuned, and for so long, we would be unable to reasonably and seperately identify them, having grown along side them for so long now.
The complex brain that forwards our existence, is always looking for a complex structure when it encloses its-self. Beware.
They are here, but they is us ~also. All of us potential biological emitters and data makers, creators and storers of informational stuff, as well .
Kind regards